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Christmassy frost flowers - or symbols of climate change?

These fragile, floral fingers of frost could help unravel a secret of climate change.

The glittering spectacle of frost flowers is a common sight on sea ice during polar springtime when the arrival of sunlight sparks a chain of chemical reactions. And now the salty ice crystals are sprouting at the University of Leeds in a chamber chilled to an Antarctic minus 60°C.

Researcher Sarah Walker explained: "The frost flowers can become very salty, because they draw up sea salt from the layer of brine that forms above the ice. And it's the salt in frost flowers that could be important for climate change."

For years, scientists have puzzled over the source of bromine monoxide which causes sharp reductions in atmospheric ozone in springtime. But rather than seeking a man-made cause, the team from the University's faculty of Earth and Environment is probing a natural answer in the ice.

Walker added: "The frost flowers potentially contribute to ozone depletion because the wind can break them up to form salty aerosols which could contribute to the formation of bromine monoxide."

Satellite data collected over Antarctica supports the theory, but the Leeds team is now growing its own frost flowers to measure the extent of this effect.

Using a high-tech piece of equipment called an aerosol time-of-flight mass spectrometer, they are analysing the salty aerosol released by frost flowers in real time.

And understanding frost flowers could also help scientists to improve their interpretation of ice cores, which provide a climate record of gases trapped within air bubbles in the ice, going back more than 720,000 years.

Notes to editors:

Higher-resolution images of the frost flowers are available for publication.

Sarah Walker is also available for interview about the work.

For further information: 

Please contact the University of Leeds Press Office on +44 (0)113 343 4031 or email

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